Recently, the virtual reality has progressed rapidly in the field of the science and technology. The coverage includes extremely various fields such as communication, design, entertainment, etc. Various VR space have been proposed and constructed by present. However, there are no VR system that realizes real time simulation based on the same physical law as it works in the real world. Then, we construct a virtual air hockey game based on rigid dynamics in this research. Moreover, to provide the presence with users, two sensations (the visual and auditory sensation) are synchronized. This paper describes various problems and their solutions in construction of virtual air hockey game system

In this research, a dialog environment between human and virtual environment has been constructed. At preset, if a person wants to interact with virtual environment, special device such a data glove is required, but it makes difficult for general users to manipulate virtual objects. When we cannot manipulate objects directly, it is natural that we ask someone with a privilege to do the operation in place of us. In the case, it is convenient if methods used in daily life are allowed. That is, the method to be proposed here is based on the integration between verbal information through the utterances and non-verbal information by the gestures such as finger pointing. The experimental results have proved the effectiveness of this approach in terms of facilitating man-machine interaction and communication. The environment constructed in this research allows a user to communicate by talking and showing gestures to a personified agent in virtual environment. A user can use his/her finger to point at a virtual object and ask him to manipulate it.

The performance improvement of radiation diagnosis devices makes it possible to get detailed medical images. The objective of this research is to develop a computer aided diagnosis system that uses advanced information of images for various kinds of internal organs and diseases. In order to make the computer aided diagnosis system do the work, as it must presume position of internal organs, the spine is used as a landmark of positional presumption. The position of each spine is recognized from the CT data, and the lungs area is extracted based on the result. We think it possible for the computer aided diagnosis system to inform radiologists about abnormality regions when the image data processing algorithm about several organs is integrated with positional presumption of organs in the future

The paper reports a system which builds assemblies by simulating in virtual space the assembly operations specified in an assembly manual. A manual consists of both illustration and explanation. Illustration consists of not only figures but also phrases and symbols which relate the phrases to the figures. This research uses the 3D models of the mechanical parts generated by a modeling tool. A noun phrase in the illustration specifies the name of a mechanical part and determines the model used. A verb phrase imposes an initial condition to be held before the execution of an assembly operation. Auxiliary lines in an illustration are virtual lines, which are used to mate the parts at both ends. Both the assembly process and terminal condition of the operation are elucidated in explanation. The state of a subassembly obtained is hard to infer due to geometric variations of the parts involved in the operation. The configuration obtained with simulation is propagated to inference mechanism and this allows the system to recognize the state of the machine assembled.

This work reconstructs a 3D graphics model of an object with specular surfaces by its rotation. Continuous images are taken to measure highlights on the smooth surfaces and their motion. Coplanar extended lights determine a plane of rays to produce a highlight stripe on the object. 3D surfaces are then recovered from the moving stripe. We investigate global motion characteristics of the highlights in the epipolar-plane images so as to qualitatively identify surface types and control the modeling process. Under single and multiple plane-of-rays illuminations, we give two quantitative approaches for surface and normal recovery which use highlight orientation in the image and highlight motion in the epipolar-plane images. The computations employ a first-order differential equation and linear equations, respectively.

A clustering-based approach to the separation of text from mixed text/graphics documents is presented. The approach starts from the grouping of connected components. Clustering is employed at three critical stages to improve the efficiency and effectiveness of the grouping, i.e., prior to the grouping, prior to orientation estimation, and posterior to the orientation estimation. Because of the high accuracy of the estimated orientation, not only the overgrouping but also most of undergrouping cases could be successfully handled.

This work reconstructs 3D graphics model of an object from an image sequence taken during the object rotation. Shading and its motion information are used in estimating shapes of smooth surfaces between fixed edges from corners and patterns. Being different from conventional shape from shadings that use one or several images, we use an image sequence that provides not only shading but also its motion. Maximum diffused shading moving on surfaces is followed at each rotation plane and surface normals are obtained. Positions of points are estimated from moving shading using motion stereo principle. It is linear equations directly achieving the results rather than iterative computation in shape from shading using complex approximation.

This paper generalizes a shape recovery method for specular surfaces. We have use linear lights that generate planes of ray to highlight a rotating object so that its specular surfaces are computed from continuous images. By setting lights properly, shape at each rotation plane can be measured and a 3D graphics model can be subsequently reconstructed. In this paper, we extend the lights used to circular ones to produce cones of ray. Under such illuminations, all surface points with different normals are highlighted in a rotation period. The computation of shape is simpler than compared with the linear light case. We give results of shape recovery on real objects.

This work explores hand-eye coordination of robots by using a camera with functions of zooming and focusing. Under the guidance of the camera, a robot hand can arrive at an object to manipulate it in the 3D space. The hand movement is decomposed into the move parallel to the image plane and the move in depth, which are controlled from image position and focus value of the hand. The focal value is put on the destination object and the hand move in depth tries to increase the image sharpness of the hand. The zooming, focusing, and 2D image position control cooperate with each other and work in feedback fashion. The fovea control of eye realized by zooming from wide-angle to tele-angle brings both flexibility and accuracy in locating hand position.

This work investigates visual characteristics of specular surfaces during rotation, and gives approaches to qualitatively identify and quantitatively recover shapes of these surfaces. Continuous images are taken when an object rotates. We look at specularly reflected patterns on the surfaces and their motion in the EPIs parallel to the rotation plane, from which estimation of each surface point and construction of the object model are carried out. We find very simple and direct methods to fulfill this objective; linear equations for multiple lights illumination, and a 1st-order differential equation for single light illumination. The motion of specular reflection has nice global characteristics in EPI. The surface types range from very shiny metal surfaces to surfaces with only week specular reflectance. We give both simulation and experiments on real objects.>

This paper proposes an approach to acquire 3D models of objects with specular reflectance for graphics use. Highlight and rotation informations are employed in the model recovery. The authors control object rotation and extract motion of a highlight stripe, from which the object shape can be qualitatively inferred and quantitatively reconstructed by solving a first-order linear differential equation. The authors have experimented on simulated and real objects to obtain their models.

Three-dimensional (3D) shape recovery from a monocular image is the inverse process of optical projection and necessitates the use of additional constraints on 3D features of the objects. We have proposed the method of shape recovery based on some hypothetical constraints and its realization by energy minimization using a parallel network. In this paper, we will discuss an extension of our proposal with the aim of correcting noise and errors in an input image through the process of shape recovery. It is hardly possible to extract edges and vertexes free from noise and errors from a real image. For the robustness of the system, we must provide our system with the ability to correct such noise and errors. In this extension, we can also modulate the inclination of the process toward model-driven or data-driven.

The authors previously presented a computer generation method of technical illustrations of a machine from its CAD model. However, parts of complicated structures in a machine are more comprehensible when they are expressed in the form of TIs which consist of several illustrations representing functional subgroups of a machine than in a picture containing the total massive structures. There arises a problem of how to divide a machine into functional parts. The authors attempt to provide an answer to it by means of processing a specific graph derived from a CAD model of a given machine. The authors propose a method based on a directed graph representing a few structural aspects of a machine. The graph represents two kinds of relations, namely inserting a part to another part and connecting parts by a gear, by directional arcs, and also the shapes of parts by distinguishably shaped nodes. The basic idea is to describe a kind of semantics by structural features of a machine in a symbolic way based on the above-mentioned mechanical relations and the shapes of parts reflecting functions of parts.>

Assembly illustrations are usually included in an assembly manual to explain assembling operations visually. It is interesting and challenging to generate an assembling plan from an illustration in an assembly manual by means of document image understanding. Most of the systems developed so far are devoted merely to convert paper-based documents into computerized forms but scarcely to deal with dynamic information acquisition from a document image. The system described in the paper aims at actually understanding a document so as to generate such a dynamic object as an assembling plan from an assembly manual.>

A method for creating a discrimination tree and its application in a machine-learning-based power fault diagnosis system are discussed. An algorithm for diagnosing a single distribution line that is developed automatically by the machine learning system is presented. The performance of machine learning for fault diagnosis using a discrimination tree, an artificial neural network, and an expert system are compared.>

We present an improved method of as- sembling plan generation from an assembly illus- tration. We have previously proposed an approach to assembly planning by recognizing auxiliary lines representing assembly relations. However some ambiguity remains in the details of assem- bling operations and also the determination of the execution order of the operations although a plan has been acquired from the pictorial features in an observed illustration. We have solved the problem by referring to the completed configuration in the succeeding illustrations. Explanatory words or phrases are also included in the illustration, which were not considered in our previous work. Through examining the parts of speech of them it is found that they can be classi- fied into two categories: 1) names of mechanical parts and 2) instructions on operations. The latter obviously conveys dynamic information necessary to the assembly planning. The former also implies dynamic information through the functions of the corresponding mechanical parts. The approach dis- cussed in this paper obtains dynamic information from explanatory words and generates an assem- bling plan by only analyzing the observing illus- tration. Index Terms -- Assembly illustration, auxiliary line, explanatory line, explanatory word, assembly relation, assembling operation, dynamic informa- tion, assembling plan ( assembly planning ).

A discussion is presented of how to understand assembly illustrations in an assembly manual without basing it on any model of mechanical parts. The discussion is based on the following two basic prerequisites. The first is that at the present stage mechanical parts are assumed to be in the shape of or composed of cylinders. The second is to recognize the 3-D-structure of mechanical parts by using the assembly information obtained from auxiliary lines. A hierarchical approach is developed to understand an assembly illustration. Also presented is a 'generated' structure understanding scheme. The scheme finds the generated structure in the succeeding illustration, by using preliminary information on the generated structure from the current assembly illustration. The preliminary information is obtained by understanding the current assembly illustration.>

An experimental task-understanding robotics system is reported that can simulate real assembly operations in an imaginary three-dimensional geometric space. The system is given as input to a set of sentences from an instruction manual elucidating mechanical assembly operations. It is considered that these sentences give a set of subgoals that must be attained for the mechanical parts to be assembled. The system must solve them and translate them into more complete command sequences by referring to three-dimensional geometric models of mechanical parts and figures attached to these sentences. Ambiguity of natural language and the assumption that readers have common-sense knowledge on assembling operations make it difficult for the system to get a correct sequence of operations.>

This new consulting system with graphical interfaces can assist a naive user in disassembling and reassembling a cylindrical machine by analyzing the structural description. Most trouble shooting systems developed so far do not tell us the way for decomposing the object to find out trouble points. If we could not know how to disassemble the object, we would be unable to inspect the trouble point. This system can assist naive users in both disassembling and reassembling an object. A user can hardly disassemble by simple command sequences that the system gave. This system automatically generates all possible procedures of disassembling the object from the 3D models. Then an integrated instruction facility using a visual interface must be offered for specifying what portion of the object should be dis/reassembled at the next stage, and for verifying whether user's operation is correct or not. And in future, a manipulator may dis/reassemble the machine instead of man. Furthermore we suggest the integrated maintenance system consisting of this consulting system and other modules.